The present invention relates to a levered tool, and more particularly to one with cooperating jaws.
A levered tool with cooperating jaws is referred to a shearing or clamping tool having two fulcra as exemplarily shown in FIG. 1 showing a pair of metal shears which includes two cooperating jaws 11, two cover plates 12, two bolts 13 pivotally bolting jaws 11 between plates 12 and forming thereat first fulcra (A), two handles 14, and two toggles 15 pivotally connected together by a bolt 16 and each of which includes a first end fixed to one of handles 14 and a second end pivotally connected to one of jaws 11 with an interconnecting joint therebetween forming thereat a second fulcrum (B). Such tool is energy-saving, however, a relatively high precision is required for the tool parts in order that the jaws 11 can be fully closed together, which means a relatively high cost of the tool. For example, if jaws 11 are found incapable of being fully closed after the tool is assembled, the tool parts can only be disassembled to be re-worked.
In an effort to overcome the above shortcoming, a levered tool having an adjusting means has been developed as exemplarily shown in FIG. 2 showing a pair of metal shears which includes two jaws 21, two cover plates 22, two bolts 23 forming first fulcra (A), two handles 24, and two toggles 25 pivotally connected by a bolt 20 and connected between jaws 21 and handles 24 with joints between jaws 21 and toggles 25 forming second fulcra (B), wherein one of toggles 25 is provided thereon with a slit 26 and includes a bolt 27 which bolts across slit 26 and has a grooved end 28 pinned by a pin 29, and each bolt 23 includes an eccentrical portion engaging with one respective jaw 21. After assembling the tool, one can rotate bolts 23 to adjust the clearance between jaws 21 by suitably engaging cam portions of bolts 23 with jaws 21 if jaws 21 are found incapable of being fully closed. If jaws 21 have a relatively large clearance therebetween after handles 24 have been fully held together, bolt 27 is screwed further on toggle 25 to reduce the gapping distance of slit 26 to inwardly translate fulcra (B) together by a small distance, in addition to a cooperative rotation of the bolt 23 having just described. Such tool, however, still suffers at least from the following disadvantage that by forcedly adjusting the gapping distance of slit 26 by bolt 27, the range that the distance between fulcra (B) can be adjusted thereby is very limited and might be insufficient in some circumstance. As an example only, if such tool is to shear or clamp a relatively large workpiece, fulcra (B) must have a distance therebetween lengthened to a relatively large extent in order that the workpiece will not easily slip out of the work space between jaws 21 upon clamping or shearing, and such relatively large distance of fulcra (B) cannot be obtained by this tool.
It is therefore attempted by the Applicant to deal with the situation described above.